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F. REVEL AND A. BOLDORINI.

ELECTRIC STEAM GENERATOR. APPLICATION FILED iULY 8,1918.

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Jnvenfo rs F. REVEL AND A. BOLDORINI.

ELECTRIC STEAM GENERATOR.

APPLlCATlON FILED JULY 8.1918.

Patented Feb. 8, 1921.

3 SHEETS-SHEET 2.

' Inv-eniors evel fl. Balalari/nz .331 mm F. REVEL AND A. BOLDORINI.

ELECTRIC STEAM GENERATOR.

APPLICATION HLED'JULY 8. 191a.

Patented Feb, 8, 1921.

3 SHEETS-SHEET 3- UNITED rare PTENT FFIQE.

FRANCESCO REVEL, OF TUBIN, AND ANGELO BOLDORINI, 'OF MILAN, ITALY.

Specification of Letters Patent.

ELECTRIC STEAM-GENERATOR.

Patented Feb. 8, 1921.

Application filed July 8, 1918. Serial No. 243,857.

utilizing high tension threephase or monophase currents, having onephase earthed, and more precisely to arrangements which permit of theinstallation and working of electric steam generators where the spaceavailable is reduced and not readily accesslble.

' This is the case, for instance, with electric generators to beinstalled on electric locomotives so as to utilize the currents that-serve as the driving agent for the production ators on ordinaryelectric locomotives is necessarily very small and of uneasy accesswhenthe train is running. The generator should therefore be of very smalldimensions because in view of the high voltages generally employed forthese locomotives,

' they'could not be attained in ordinary steam generators, withoutresorting to the insulat- 1n:g,cliaphragms .that form the object of thepresent improvements. Furthermore the steam generator should be capableof working without need of special attendance, and should consequentlyadjust its own steam production automatically to suit the steam callswhich may vary from one moment to the next, the distribution pressurebeing maintained approximately constant.

One of the methods of realizing the said objects according to theinvention and also of directly utilizing in the steam generators thesame currents-in a general way-that are used for the electric tractionis illustrated, only by way of example of the various dispositions thatmay be given to the said improvements, in the annexed drawing in which:

Figures 1 and 2 show in vertical and horizontal section respectively oneor" the constructions that may be adopted when the current available isthreophase, with one of the phases earthed, and when unbalanced loadconditions are of no inconvenience.

Fig. 3 shows in section a likewise threephase construction, with onephase earthed, when balanced load conditions are desired in the threephases.

Fig. 4 shows a controlling device therefor to maintain a constantpressure of the proa duced steam.

Fig. 5 shows an automatic device "for limiting the water level so thatit cannot exceed a desired height.

l The steam generator proper consists of a single chamber R, or of twoor three chambers forming a single block or independent from oneanother, the chambers being made of cast iron or steel plates andsuitably connected with one another. The chambers communicate with oneanother both at the bottom T, where the water inlet is provided, and atthe top V that forms the steam space, so that the same water levelobtains in all of them.

The chambers or containers R are fitted witha common steam-tight lid Corwith separate steam tight lids, through which are led the iron rods G,suitably insulated from the lids C by means of insulators C andsupporting the electrodes E that carry the current to the water in thewater space.

When one of the phases is earthed, one of the electrodes is supplied bythe container walls or portions thereof, as in Figs. 1 and 2, whichrepresent an unbalanced threephase system. In the balanced threephasesystem illustrated in Fig. 8 two electrodes, for instance aand b-, areinsulated and ,the third one -cis electrically connected celain, quartzor other insulating material, the inner cylinder being provided with oneor more openings staggered relatively to the openings of the outercylinder (Fig. l). The diaphragins may also consist of a cylinderconnected to a set of three walls ar ranged to form a triangle insidethe cylinder and fitted with an opening f each. he object of thediaphragms is:

1. To insulate the electrodes and the water, by which the electrodes aresurrounded, from the metallic mass of the containers where necessary;

2. To suitably lengthen, as indicated by dotted lines in Figs. 2 and 3,the path which the electric current has to traverse across the water inorder to travel from the electrodes to the wall portions that are eftuncovered by the insulator in the case of Fig. 1, or from one electrodeto the other in the case of Fig. 3.

3. T 0 form partitions in the containers, in order to lessen the washingmotions which the locomotive tends to impart to the water mass whentraveling.

The water is fed into the steam generator by a motor driven pump of asuitable output somewhat in excess of the generators maximum output.

The pressure of the steam produced is maintained constant (Fig. 4-) bydischarging the amount of water that is fed into the container in excessof the steam call obtaining at any given moment. Any water surplus fedthrough ,-aa' into the boiler, causes the water level to rise in thecontainer, and consequently the steam production and steam pressure torise too. Owing to the increased steam pressure, the lift of theoverflow valve s, which had been set for a certain constant pressure, isincreased too and the surplus water will thus escape through the valve.

\Vhen the available feed water is of such a quality as to cause toolarge a proportion between the electrodes should be blown ofi.

This is attained by means of the arrange ment shown by Way of example inFigs. 1 and 2, and lettered A, which represent a blow-off devicearranged in the electrode region. This discharging device may beconnected to the pressure regulating valve in such a way that by theoperation of a three way cock the said valve can be made to dis chargethe excess water either from the bottom of the boiler (cold water) orfrom the electrode region (hot water) or from both. The hot blown-oilwater is made to traverse the pipe coil of a feed water heater in orderto recover the heat contained in the blow-01f.

Owing to constructional considerations the diaphragms cannot be made toextend into the space which is normally intended as steam space, as itis necessary to prevent the water level from reaching the saidunprotected region, where it would give rise to short-circuits.

The following advantages are thus obtained:

l. The maximum input of electric energy in the electric steam generatoris automatically limited.

2. The maximum amount of electric energy absorbed by the steam generatorcan be ad just-ed even from a distance, to suit the current available.

3. The complete filling oi the electric boiler through wrong operationof the regulating devices or through the latter getting out of order ismade impossible.

The attendant is consequently warned not to switch on the current when,after a stand still, he should find the boiler full of water and thefilling when the boiler is at work prevented. This object is reachedthrough a device of which Fig. 5 is a diagrammatic illustration. Thedevice comprises a metallic contact button B projecting inside thecontainer R and. electrically insulated from the containefs body bymeans of insulators C". This button is connected in an auxiliarylow-voltage circuit in which is inserted a relay actuating the controlswitch Q of the motor-pump set M or, failing this switch, theelectro-magnetically operated coclr controlling the water teed. One endof the relay winding is connected to the boiler body, so that the water,when reaching a predetermined level, closes the relay circuit either bydirect contact with the insulated button, or indirectly through theintermediation of a float. The relay L, its winding being now traversedby the current, opens the control switch Q of the m0- tor-pump set M orcloses the feed valve.

Having now fully described our said invention what we claim is:

1. In an electric steam generator, a. casing, electrodes therein,insulating diaphragms in the casing and provided with openingsinterposed between the electrodes with the object of increasing thelength of the resistance represented by the water separating theelectrodes, and of reducing the wash-motions of the generator water whenthe locomotive or carriage on which the generator is installed istraveling.

2. In an electric steam generator a casing. a cylindrical diaphragmarranged against the inner surface of the casing, a plurality ofelectrodes in the diaphragm but spaced therefrom, a plurality ofdiaphragms arranged to form a triangle within the cylindrical diaphragmand coacting with the adjacent portion of the cylindrical diaphragm informing a chamber for the adjacent electrode and in addition beingprovided with an opening to increase the length of the resistancerepresented by the water separating the electrodes and of reducing thewash actions of the generator water when the locomotive or carriage onwhich the generator is stalled is traveling. j 3. In an electric steamgenerator as claimed in claim 2, an automatic adjustable spring-loadedregulating valve for dischargingfrom the water space, a large or smallamount of feed or hot water and in consequence regulating the steamproduction.

4. In an electric steam generator as claimed in claim 2, a jacketsurrounding and arranged in communication with the casing,

and a manually operable discharge valve fitted to the jacket.

5. ,In an electric steam generator as claimed in claim 2 a feed waterpipe for the casing, a jacket surrounding and com- I municating with thecasing, a pressure regulating valve mounted in the feed water pipe,

a pipe leading from the jacket and connected to the valve, a three wayvalve arranged for discharging hot water from the electrode region orfrom the bottom of the casing and a pipe coil in the feed water heaterthrough which the hot blown-ofii water passes.

6. In an electric steam generator as claimed in claim 2, a feed waterpipe leading to the casing, a pump interposed in the pipe, a motoroperatively connected with the pump, a float in thecasing, a metallicbody connected with the float, an electric contact arranged inside ofthe casing and coming into action when the water reaches a predeterminedlevel, either through the water coming directly in touch with thecontact, or through contact with the metallic body on the float, and acontrolling switch in circuit with the contact and motor.

In testimony whereof we afiix our signatures.

FRAlN CESCO REVEL, INGEGNERE. ANGELO BOLDORINI.

